Lifting-jack



` 2 Sheets-Sheet 2.

(Mmm D. H.. MORRISON.

' Lifting-Jack. No. 228,830. y Patenteollune15,`1880.

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j I' L L j a a .flZes/ odd/d6 `ilNrTnn STATES PATENT Ormea.,

DAVID H. MORRISON, OF DAYTON, OHIO.

LlFTlNG-JACK.

l SPECIFICATION forming part of Letters Patent No. 228,830, dated June15, 1880.

Application inea April 2t, 1880. No model.)

To all whom t may concern Be itknown that I, DAvrD H. MORRISON, ofDayton, in the county of Montgomery' and State of Ohio, have inventedcertain new and useful Improvements in Lifting-Jacks; and I do herebydeclare the following to be a full, clear, and exact description of thesame.

My invention relates to an improvement in that class of lifting-jackswhich employ rack lifting-bars instead of screws, and my object is toproduce a jack which in its operating parts shall be as free as possiblefrom friction, and shall be capable of raising extremely heavy objectswithout liability of its parts breaking or giving away.

The novelty of my invention consists in em-l ployingin a jack thecombined forces of a toggle an d cani or eccentric pressure for alifting power, with the parts so arranged that lirm solid bearings areobtained for the rack-operating devices, which re-enforce each other anddo not depend upon pivot pins or bolts, and whereby the frictionoccasioned by the operation of these parts is reduced to a minimum.

The novelty further consists in the construction and combination of theparts, all as will be herewith .set forth and specically claimed.

In the accompanying drawings, Figure l is a perspective view of myimproved jack. Fig. 2 is a central sectional view, in side elevation, ofthe same. Fig. 3 is a rear elevation of the middle portion of the jack.

rEhe shell or casingA may be of any desired construction. In thisinstance it is supported by a base, B, with lateral ribs or webs C, todistribute the strain; and it contains three compartments-one for thelifting rack-bar, a second for the holding-dog, and the third for thelifting mechanism. The rack-bar D carries upon its top, which projectsfrom an opening in the case, the usual or any serrated headpiece, andits lower end is formed into a foot, a, somewhat narrower than therack-bar, which foot projects through a vertical slot of correspondingsize in the front plate of the case, as represented.

rIlhe division-wall E, in connection with the side and front walls ofthe case, form a snug sheath for the rack-bar, and allow it only avertical play. The foot c is used in 'starting to raise objectssufficiently to get the head of the lifting-bar under them, or to raiseobjects for a short distance only, and being narrower than the rack-bar,of which it forms a part, said bar has a bearin g upon the front plateof the case on each side of the slot. f

In the bottom of the liftiug-niechanism compartment of the case is anintegral pillow-block or step, b, in the recess ot' which is supported avibrating arm or bar, F, of the shape shown, having its upper endconcave to form a socket for the earn bearii'lg-surfaces 0 of theactuatinglever G. This lever. of the shape represented, is provided witha socket for the handle H, and is supported in the case by the vibratingarm F, upon which the integralcani c rests and with which itarticulatcs, and by a bolt, e, which, passing through the leverconcentrically with the cam d, has upon its ends square heads or nuts f,which are confined in vertically oblong rectangular apertures ormortises g in the sides of the case, as shown particularlyin Fig. l;also, hung upon the bolt or pin e, straddling the cam d, and bearingthereon, is the slotted lifting-dog I, Figs. 2, and 3, which is inclinedtoward the rack-bar, with which it engages at its upper end by means ofthe teeth t', as represented. The head or upper end of the dog isprovided with a lateral stud or knob, j, which projects through anaperture, 7c, in the side of the case, as seen in Fig. 1. If desired,there may be two knobs, one projecting on each side throughcorresponding apertures in the sides of the case. rIhesc aperturesshould be of sufticient size to permit the necessary vertical movementof the dog in raising the rack-bar and the necessary'swinging motion indisengaging itself from the rack-bar and descending to its formerre-engaging position.

It is to be observed that while the bearing portions c d of the leverare segments of true circles, yet they are located eccentrically to eachother, and practically form cam bearingsurfaces, of which the lower one,c, traveling in the socket of the vibrating arm F, as the lever isbrought down, causes the upper one, d, to rise as it turns, thus forcingthe dog I upward and raising the rack-bar.

It is to be further noticed that while the le- IOO ver is descending andthe segment d is rising as it turns on its center, the cam c is also,while turning, swinging in the arc of a circle upon the shifting centerofthe segment d. This motion of the cam 0 causes the arm Fto move inwardwith the effect of a toggle, and thus increases the lifting effect ofthe cam.

It is also to be observed that while the dog l is being raised it doesnot change its inclination, but moves directly up, so thatits force isexerted always in the same line, ruiming through its points of greatestresistance. This motion ot' the dog while ascending is due to the headsot' the bolt e being'conned in the vertical apertures g, and, further,to the upper end ofthe dog engaging with the rackbar, which is limitedto a vertical motion by its sheath.

It is to be particularly noticed that while the pin e serves to connectthe parts, it is in no sense a t'ulcrum, but that all the strain andforce is borne by the solid members, which, articulating as they do,resolve it upon the base of the jack, which is lirmly supported.

The dog` l is further so set or inclined that when the operating-leveris raised it falls into engagement with the rack-bar by its gravity whenthe jack is upright; but to insure `its positive engagement in anyposition in which the jack may be placed, I have formed sufticient swellin that portion ot' the web of the lever which enters the slot l of thedog to cause the contact of said swell m with the end wall of the slot,when the lever is raised and the teeth of the pawl are just on the pointof engaging with the rack-bar, so as to force the dog into engagementwith the rack-bar itI its own weight and then position is notsuiticient.

To hold the rack-bar up at each successive hoist I employ a gravitatingdog, L, which is seated in a recess in the upper compartment ot' thecase, as seen in Fig. 2. This seat for the dog` is formed by thedivision-wall n, integral with the case, and the dog L issuflicientlyinelined to insure its engagement by its gravity. It has aseries of engaging teeth, 0, as represented, and is free to vibrate uponits solid seat without the employment of pivot-pins. Like the dog I, ithas a stud or knob, p', projecting 'from its upper end, whichextendsthrough an aperture, 1', in the side of the case. YV hen it is desiredto lower the rack-bar it is only necessary' to disen gage the dogs I andL successively or simultaneously by means ot' the `knobs j and p.

The shape of the teeth of the rack-bar is im materiahprovided the dogswill be automatically released. The form herein shown is,'however7considered best for strength.

The principles of construction and opera-4 tion involved in my jackproduce an implement which issimple, durable, and extremely powerful,with a minimum of friction.

Having thus fully described my invention, I claiml. In a lifting-jack,the combination, with the rack-bar, of a lifting-dog, a vibratingsupport-arm, andan interposed cam or its equivalent, whereby, uponturning said cam or its equivalent, a combined toggle and campressure-is exerted upon the rack-bar.

2. In a lifting-jack, the combination, with the rack-bar, ot' alifting-dog having' a fixed unvarying upward motion, a vibratingsupport-arm, and an interposed actuating-cam, substantially asdescribed.

3. In a lifting-jack, the combination, with the rack-bar, of alifting-dog, a vibrating support-arm set in a solid socket, and aninterposed actuatingcam, substantially vas described.

4. In a liftingjack, the actuating-'lever having at its llower end a cambearing-surface articulating with a vibrating arm, and having also asecond bearing-surface turning on a shifting center, in combinationwit-h a lifting'- dog and its engaging rack-bar, substantially asdescribed.

5.v In a lifting-jack, the combination, with a lifting-dog, anactuating-cam, and a vibrating toggle-arm, of a bolt or pin connectingsaid dog and actuating-cam, and having upon its ends square `orrect-angular heads recessed in vertically-oblong slots,substantially asand for the purpose specied.

6. Ina lifting-jack, the combination of the lifting-dog, a vibrating armset in a solid socket, and an interposed actuating-cam, the parts beingsovconneeted and articulated that the lifting-strain is thrown directlyupon the solid support of the 4vibrating arm, substantially asdescribed.

7. In a lifting-jack, vthe combination, with lifting-dog, of itsactuating-lever, the parts being so arranged that the lever serves tothrow the dog into engagement with its rackbar at each upward stroke,substantially as described.

S. In a lifting-jack, the swinging gravitating dog L, vset in a solidisocket integral with the shell of the "jack, land provided with areleasing pin or'knob extending to the outside, substantially asdescribed.

In testimonyl whereof I have hereunto set my hand.

DAVID H. MORRISON.

Witnesses:

P. H. GUNoImL, GHAs. M. PEcK.

IOO

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